Information record medium, apparatus for recording the same and apparatus for reproducing the same

ABSTRACT

An information record medium ( 1:  DVD) has a record track ( 1   a ) to be reproduced by an information reproducing apparatus (S 2 ). The information reproducing apparatus is provided with a read device ( 80 ) and reproduces audio information by a predetermined audio frame unit while relatively moving the read device along the record track recorded with at least the audio information by the audio frame unit. A plurality of audio packets ( 43, 202 ) are arranged along the record track, in each of which audio information pieces ( 207 ) constructing the audio information sampled by a predetermined sampling frequency and audio control information ( 203 ) for controlling a reproduction of the audio information pieces by the information reproducing apparatus are respectively recorded. The audio control information is provided with time management information ( 203   f : PTS) for specifying a time, by a predetermined specification frequency, to manage a timing of outputting the audio information, which is included in the audio frame which head is positioned in the audio packet including the audio control information, in the reproduction by the information reproducing apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information record medium such as anoptical disk of a high recording density type, which is capable ofrecording information such as video information, audio information andthe like at a high density, and which is represented by a DVD (DigitalVideo or Versatile Disk). The present invention also relates to arecording apparatus for recording the information onto the informationrecord medium, and a reproducing apparatus for reproducing theinformation from the information record medium.

2. Description of the Related Art

Conventionally, a so-called LD (Laser Disk) and a so called CD (CompactDisk) are generalized as optical disks, on which information such asvideo information, audio information and the like is recorded.

On the LD, the CD or the like, the video information and the audioinformation are recorded together with time information indicating atime at which each information is to be reproduced with respect to areproduction start position, which each LD or the like has, as astandard position. Thus, other than a general normal reproduction toreproduce the recorded information in the order of recording, variousspecial reproductions are possible, such as a reproduction to extractand listen to an only desirable music out of a plurality of recordedmusics, a reproduction to listen to the recorded musics in a randomorder and so on, in case of the CD, for example.

However, there is a problem that, according to the above mentioned CD,LD or the like, a so called interactive and variegated reproduction isnot possible in which the audience can have a plurality of selectionbranches as for the video or audio information to be displayed orsound-outputted and in which the audience can select them to watch orlisten to it.

Namely, for example, in case of giving audience to a foreign movie onthe LD, it is not possible to select one of languages to be used for asubtitle (caption) displayed on the picture plane (e.g. select one ofthe subtitle in Japanese and the subtitle in the original language) soas to display the subtitle in the selected language, or, in case ofgiving audience to a music recorded on the CD, it is not possible toselect one of sound voices of the music (e.g. select one of the Englishlyric and the Japanese lyric).

On the other hand, various proposals and developments are being made asfor the DVD, as an optical disk in which the memory capacity is improvedby about ten times without changing the size of the optical disk itselfas compared with the aforementioned conventional CD. According to theknowledge of the present inventors, it is anticipated that it ispossible, as for the DVD having such a large memory capacity, to: divideaudio information, video information or the like by an appropriatelength respectively into an audio pack, a video pack or the like; addadditional information such as header information to each pack; switchand multiplex these packs; and reproduced the multiplexed audioinformation, video information or the like.

However, in the field of the audio or video related technique, the audioinformation, the video information or the like is generally treated in arelatively large unit e.g. a so called audio frame or video frame, atthe time of recording, editing and reproducing by the recordingapparatus and the reproducing apparatus. Thus, for example, assumingthat the frequency of this audio frame is 75 Hz, which is the same asthe case of CD, the compatibility in frequency of the audio frame isgenerally bad with the audio pack, the video pack or the likemultiplexed in the aforementioned DVD. This results in that a verycomplicated reproduction method is estimated to be necessary. Further,in the technical art of the DVD, the actuality is such that a personhaving an ordinary skill in this art does not even recognize the subjector problem itself that the compatibility in frequency of the audio frameused in the conventional CD etc. is bad with the audio pack etc. whichis expected to be usable in the aforementioned DVD,

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide aninformation record medium, on which the audio information, which is tobe recorded, edited and reproduced by the unit of audio frame, isrecorded in a form of being divided by an appropriate length andmultiplexed, can be relatively easily recorded, edited and reproduced,and also provide an apparatus for recording the same, and an apparatusfor reproducing the same.

The above object of the present invention can be achieved by aninformation record medium having a record track to be reproduced by aninformation reproducing apparatus, which is provided with a read deviceand reproduces audio information by a predetermined audio frame unitwhile relatively moving the read device along the record track recordedwith at least the audio information by the audio frame unit. In theinformation record medium of the present invention, a plurality of audiopackets are arranged along the record track, in each of which audioinformation pieces constructing the audio information sampled by apredetermined sampling frequency and audio control information forcontrolling a reproduction of the audio information pieces by theinformation reproducing apparatus are respectively recorded. The audiocontrol information is provided with time management information forspecifying a time, by a predetermined specification frequency, to managea timing of outputting the audio information, which is included in theaudio frame which head is positioned in the audio packet including theaudio control information, in the reproduction by the informationreproducing apparatus. And that, a frequency of the audio frame and afrequency of the audio packet are prescribed such that the frequency ofthe audio frame is 1/n (n: natural number) of the sampling frequency and1/m (m: natural number) of the specification frequency, and a dataamount of the audio information included in one audio packet is morethan a data amount of one audio frame.

According to the information record medium of the present invention. Ineach of the audio packets arranged along the record the audioinformation pieces constructing the audio information sampled by apredetermined sampling frequency and the audio control information arerespectively recorded. The audio control information is provided withtime management information. The time management information specifies atime, by a predetermined specification frequency, to manage a timing ofoutputting the audio information, which is included in the audio framewhich head is positioned in the audio packet including the pertinentaudio control information, in the reproduction. At this time, since thefrequency of the audio frame is 1/n of the sampling frequency, it ispossible to avoid a case where the audio frame is cut in the middle ofsampling. Further, since the frequency of the audio frame is 1/m of thespecification frequency, the accuracy of the time specified by the timemanagement information can be kept high. Furthermore, since the dataamount of the audio information included in one audio packet is morethan the data amount of one audio frame, every one of the audio packetscan include the time management information respectively. As a result,such a problem is never caused that, because the time managementinformation randomly exists or not exists in the audio packet, therecording position of the information after the time managementinformation is shifted in a random or unknown manner. For example, it ispossible to cut reading one portion of the audio control information,which is not shifted, of the bytes in the constant number in the audiopacket, and to speedily read another portion of the audio controlinformation, which is necessary for the reproduction, by use of a rathersimple algorithm.

Accordingly, the construction of the information recording apparatus orthe information reproducing apparatus for the DVD etc. can besimplified, and the production cost thereof can be reduced.

In one aspect of the information record medium of the present invention,the information record medium has the record track to be reproduced bythe information reproducing apparatus, which reproduces videoinformation by a predetermined video frame unit in addition to the audioinformation while relatively moving the read device along the recordtrack recorded with at least the video information by the video frameunit in addition to the audio information. In this aspect, a pluralityof video packets are multiplexed with the audio packets and arrangedalong the record track, in each of which video information piecesconstructing the video information and video control information forcontrolling a reproduction of the video information pieces by theinformation reproducing apparatus are respectively recorded. And that,the frequency of the audio frame and a frequency of the video frame areprescribed such that the frequency of the audio frame is equal to aninteger multiple of the frequency of the video frame.

According to this aspect, the video packets are multiplexed with theaudio packets, and arranged along the record track. In each of the videopackets, the video information pieces constructing the video informationand the video control information are respectively recorded. At thistime, since the frequency of the audio frame is equal to an integermultiple of the frequency of the video frame, it is possible tosynchronize the video information and the video information.Accordingly, a complicated signal process for compensating thedifference in the time between the audio information and the videoinformation is not necessary at the time of a signal process such as arecording process, an editing process, a reproducing process and thelike. Therefore, the meaning of “equal to the integer multiple of thefrequency” here is that the frequencies are equal to each other in sucha degree that these two kinds of audio frame and the video frame can besynchronized with each other by the actual reproducing apparatus, andthat the degree of the equality thereof is determined suitably independence upon the ability of the reproducing apparatus and theproperty of the signal which are actually used.

Accordingly, the construction of the information recording apparatus orthe information reproducing apparatus for the DVD etc. in which thevideo information as well as the audio information is dealt with, can besimplified, and the production cost thereof can be reduced.

In this aspect, there may be a plurality of different kinds offrequencies as the frequency of the video frame, and the frequency ofthe audio frame may be preferably prescribed to be equal to a leastcommon multiple of the different kinds of frequencies.

According to this aspect, since the frequency of the audio frame isequal to a least common multiple of the different kinds of frequencies,the audio information and the video information can be substantiallysynchronized with each other, as for a plurality of different types ofvideo information such as the information based on the NTSC method, thePAL (SECOM) method, the Hi vision method or the like, for example, sothat it is advantageous at the time of recording, editing andreproducing.

Accordingly, the construction of the information recording apparatus orthe information reproducing apparatus for the DVD etc. in which thevideo information based on the NTSC method, the PAL method or the like,as well as the audio information is dealt with, can be simplified, andthe production cost thereof can be reduced.

In another aspect of the information record medium of the presentinvention, the frequency of the audio frame is 600 Hz. 750 Hz. 1200 Hz.1500 Hz, 3000 Hz or 6000 Hz.

Accord to this aspect, since the frequency of the audio frame is one of600 Hz, 750 Hz, 1200 Hz, 1500 Hz, 3000 Hz or 6000 Hz, in case ofrecording the PCM linear audio data as the audio information into theaudio packet, every one of the audio packets can include the timemanagement information respectively. Further, the audio information andthe video information can be synchronized with each other, as for thevideo information based on the NTSC method, the PAL method or the HiVision method, so that it is advantageous at the time of recording,editing and reproducing.

Accordingly, the construction of the information recording apparatus orthe information reproducing apparatus for the DVD etc. in which thevideo information based on the NTSC method, the PAL type or the like, aswell as the audio information is dealt with, can be simplified, and theproduction cost thereof can be reduced.

The above object of the present invent ion can be also achieved by aninformation recording apparatus for recording information onto the abovedescribed information record medium of the present invention. Theinformation recording apparatus is provided with: a record device forrespectively recording, into a plurality of audio packets arranged alongthe record track, audio information pieces constructing the audioinformation sampled by a predetermined sampling frequency and audiocontrol information for controlling a reproduction of the audioinformation pieces by the information reproducing apparatus, the audiocontrol information is provided with time management information forspecifying a time, by a predetermined specification frequency, to managea timing of outputting the audio information, which is included in theaudio frame which head is positioned in the audio packet including theaudio control information, in the reproduction by the informationreproducing apparatus; and an input device for inputting at least oneportion of the audio control information. And that, a frequency of theaudio frame and a frequency of the audio packet being prescribed suchthat the frequency of the audio frame is 1/n (n: natural number) of thesampling frequency and 1/m (m: natural number) of the specificationfrequency, and a data amount of the audio information included in oneaudio packet is more than a data amount of one audio frame.

According to the information recording apparatus of the presentinvention, the audio information pieces constructing the audioinformation sampled by a predetermined sampling frequency arerespectively recorded into a plurality of audio packets arranged alongthe record track, by the record device. Along with this, as at least oneportion of the audio control information provided with the timemanagement information is inputted by the input device, the audiocontrol information is recorded into each of the audio packets, by therecord device. The time management information specifies a time, by apredetermined specification frequency, to manage a timing of outputtingthe audio information, which is included in the audio frame which headis positioned in the pertinent audio packet including the audio controlinformation, in the reproduction. At this time, since the frequency ofthe audio frame is 1/n of the sampling frequency and 1/m of thespecification frequency, and since the data amount of the audioinformation included in one audio packet is more than the data amount of(one audio frame, the above described information record medium of thepresent invention can be recorded and obtained.

In one aspect of the information recording apparatus of the presentinvention, the information recording apparatus records onto the abovedescribed one aspect of the information record medium of the presentinvention. In this aspect, the record device respectively records, intoa plurality of video packets multiplexed with the audio packets andarranged along the record track, video information pieces constructingthe video information and video control information for controlling areproduction of the video information pieces by the informationreproducing apparatus. And that, the frequency of the audio frame and afrequency of the video frame are prescribed such that the frequency ofthe audio frame is equal to an integer multiple of the frequency of thevideo frame.

According to this aspect, the video information pieces constructing thevideo information and the video control information are respectivelyrecorded into a plurality of video packets multiplexed with the audiopackets and arranged along the record track, by the record device. ATthis time, since the frequency of the audio frame is equal to an integermultiple of the frequency of the video frame, the above described oneaspect of the information record medium of the present invention can berecorded and obtained.

The above object of the present invention can be also achieved by aninformation reproducing apparatus for reproducing information from theabove described information record medium of the present invention. Theinformation reproducing apparatus is provided with: a read device forreading information recorded at a predetermined reading position on therecord track; a movement device for relatively moving the read devicealong the record track; an extract device for extracting the audiopacket from the information read by the read device; and an audio decodedevice for decoding the audio information included in the extractedaudio packet by the audio frame unit on the basis of the time specifiedby the time management information included in the extracted audiopacket.

According to the information reproducing apparatus of the presentinvention, while the read device is relatively moved along the recordtrack by the movement device, the information recorded at apredetermined reading position on the record track is read by the readdevice. Then, the audio packet is extracted from the information read bythe read device, by the extract device. Finally, the audio informationincluded in the extracted audio packet is decoded by the audio frameunit on the basis of the time specified by the time managementinformation included in the extracted audio packet, by the audio decodedevice. Therefore, it is possible to easily reproduce the abovedescribed information record medium of the present invention.

In one aspect of the information reproducing apparatus of the presentinvention, the information reproducing apparatus reproduces theinformation from the above described one aspect of the informationrecord medium of the present invention. In this aspect, the extractdevice extracts the audio packet and the video packet separately fromthe information read by the read device. And that, the informationreproducing apparatus is further provided with a video decode device fordecoding the video information included in the extracted video packet bythe video frame unit.

According to this aspect, the audio packet and the video packet areseparately extracted from the information read by the read device, bythe extract device. Then, the video information included in theextracted video packet is decoded by the video frame unit, by the videodecode device. Therefore, it is possible to easily reproduce the abovedescribed one aspect of the information record medium of the presentinvention.

In another aspect of the information reproducing apparatus of thepresent invention, the audio decode device decodes the audio informationwhile cutting one portion of the audio control information other thanthe time management information included in the extracted audio packet.

According to this aspect, the audio information is decoded while cuttingone portion of the audio control information other than the timemanagement information included in the extracted audio packet, by theaudio decode device. At this time, since every one of the audio packetsincludes the time management information respectively, and since therecording position of the information after the time managementinformation is not shifted due to the existence and non existence of thetime management information, this process of cutting one portion of theaudio control information can be performed by use of a relatively simplealgorithm.

Accordingly, the construction of the information reproducing apparatusfor the DVD etc., can be simplified, and the production cost thereof canbe reduced.

The nature, utility, and further features of this invention will be moreclearly apparent from the following detailed description with respect topreferred embodiments of the invention when read in conjunction with theaccompanying drawings briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a physical structure of record informationof a DVD as one embodiment of the present invention;

FIG. 1A is a perspective view of the DVD in FIG. 1;

FIG. 2 is a diagram showing a logical structure of the recordinformation of the DVD in FIG. 1;

FIG. 3 is a diagram showing a structure of an interleaved unit of theDVD in FIG. 1;

FIG. 4 is a table showing the specification of PCM linear audio datarecorded on the DVD of FIG. 1;

FIG. 5 is a diagram showing one example of the arrangement of sampledata in the PCM linear audio data of FIG. 4;

FIG. 6 is a diagram showing another example of the arrangement of sampledata in the PCM linear audio data of FIG. 4;

FIG. 7 is a diagram showing another example of the arrangement of sampledata in the PCM Linear audio data of FIG. 4;

FIG. 8 is a diagram showing a physical data structure of the audio packon the DVD of FIG. 1;

FIG. 9 is a table showing the number of quantized bits, the number ofsamples and the data size of data in each packet for the specificationof the PCM linear audio data of FIG. 4;

FIG. 10 is a table showing a concrete data structure of the packetheader of the audio pack of FIG. 8;

FIG. 11 is a table showing a concrete data structure in a private areain the packet of the audio pack of FIG. 8;

FIG. 12 is a block diagram of an information recording apparatus forrecording the DVD in FIG. 1, as another embodiment of the presentinvention; and

FIG. 13 is a block diagram of an information reproducing apparatus forreproducing the DVD in FIG. 1, as another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the accompanying drawings, embodiments of the presentinvention will be now explained. The following explanations will be donefor the embodiments, in which the present invention is applied to theaforementioned DVD.

(I) Embodiment of Information Record Medium

First of all, a physical structure and a logical structure as well as anoperation of a DVD, as one embodiment of the information record mediumto which the present invention is applied, will be explained withreference to FIGS. 1 to 11.

At first, a record format of video information and audio information ona record track of the DVD (i.e. a physical record format) is explainedby use of FIG. 1.

As shown in FIG. 1, a DVD 1 as the present embodiment is provided with alead in area L1 at its most inner circumferential portion and a lead outarea L0 at its most outer circumferential portion, between which videoinformation and audio information are recorded along the record tracksuch that they are divided into a plurality of VTSs 3, each of which hasa unique ID (Identification) number (i.e. VTS#1 to VTS#n). Here, the VTS(Video Title Set) 3 is a set (bundle) of titles (each of which is oneproduction or one work which an author or producer intends to offer tothe audience), which are related to each other (e.g., which attribute,such as the number, the specification, the corresponding languages etc.of audio and video streams is the same to each other). More concretely,a plurality of movies which are related to the same movie to each otherbut which languages of serifs (lines) are different from each other maybe recorded as different titles respectively, or even in case of thesame movies, the theater version and the special version may be recordedas different titles respectively. Ahead of the area where the VTSs 3 arerecorded, a video manager 2 is recorded as shown in FIG. 1. As theinformation recorded in the video manager 2, for example, informationrelated to the whole video and audio information recorded on the DVD 1,such as a menu for accessing each title, information for preventing anillegal copy, an access table for directly accessing each title and soon, is recorded.

These video, audio and control informations are recorded on a spiral orcoaxial record track la of the DVD 1 as shown in FIG. 1A.

One VTS 3 is recorded such that it is divided into a plurality of VOBs10, each of which has an ID number (VOB ID#1, VOB ID#2, . . . ) andcontrol data 11 disposed ahead of the VOBs 10. Here, a data portionconstructed by a plurality of VOBs 10 is defined as a VOB set (VOBS) asshown in FIG. 1. This VOB set is defined to distinguish the VOB 10,which constructs one portion of the VTS 3 as the substantial portion ofthe video and audio information, from the control data 11, whichconstructs another portion of the VTS 3.

In the control data 11 recorded at the head of the VTS 3, informationsuch as PGCI (ProGram Chain Information), which is various informationrelated to a program chain as a logical division obtained by combining aplurality of cells (the “cell” will be described later in detail), isrecorded. In each VOB 10, the substantial portion of the video and audioinformation (i.e. the video and audio information itself other thancontrol information besides the control information are recorded.

Further, one VOB 10 is constructed of a plurality of cells 20, each ofwhich has an ID number (cell ID#1, cell ID#2, . . . ). Here, One VOB 10is constructed such that it is completed by the plurality of cells 20and that one cell 20 does not strides over two VOBs 10.

Nextly, one cell 20 is constructed of a plurality of VOB units (VOBUs)30, each of which has an ID number (VOBU#1, VOBU#2, . . . ). Here, theVOB unit 30 is an information unit, each of which includes the videoinformation, the audio information and sub picture information (which isdefined as information of a sub picture such as a subtitle of a movieetc.).

One VOB unit 30 is provided with: a navi pack (a navigation pack) 41 forstoring various control data; a video pack 42 for storing video data; anaudio pack 43 for storing audio data; and a sub picture pack 44 for subpicture data. Here, in the video pack 42, a packet including the videodata together with additional information such as header thereof isrecorded. In the audio pack 43, a packet including the audio datatogether with additional information such as header thereof is recorded.Further, in the sub picture pack 44, a packet including graphics such asa character and a diagram as the sub picture, together with additionalinformation such as header thereof, is recorded. In the video packs 42,which data amount is relatively large as shown in FIG. 1, one or aplurality of GOPs are recorded within one VOB unit 30. The audio pack 43and the sub picture pack 44 are disposed intermittently between thevideo packs. 42.

It is prescribed by a standard specification of the DVD that there are 8kinds of audio recordable on the DVD 1 while 32 kinds of sub picturerecordable on the DVD 1. Further, there always exists the navi pack 41in one VOBU 30. On the other hand, there may not exist each of the videopack 42, the audio pack 43 and the sub picture pack 44 in one VOBU 30,or, even in case that these packs exist in one VOBU 30, the number ofthe packs and the order of the packs are freely determined.

Finally, the navi pack 41 is provided with: a DSI (Data SearchInformation) packet 51 including search information to search a videoimage or an audio sound desired to be displayed or sound-outputted(concretely, search information such as an address, where the video oraudio to be displayed or sound outputted is recorded, on the DVD 1); anda PCI (Presentation Control Information) packet 50 including informationrelated to a display control at a time of displaying the video image oroutputting the audio sound, which is searched on the basis of theinformation of the DSI packet 51. Further, the video data included inone VOBU 30 consist of at least one GOP (Group Of Pictures). In the PCIpacket 50, high light information, which defines a display or operationat a time when one selection item is selected out of selection items bythe audience, is included. By the high light information, for example,the change of the picture plane display as well as the display positionto be changed with respect to the selection item selected on a specialpicture plane of selection items (i.e. a so called menu picture plane)for the audience to select, and the command corresponding to theselected item (i.e. a command to be performed in correspondence with theselected item) are set.

The video information to Construct and display a frame, a selectionbutton and the like, which is required to construct and display the menupicture plane, is recorded in the sub picture pack 44 as the sub pictureinformation.

Further, the above described GOP is a minimum picture unit, which can beindependently reproduced and which is determined by a standard based onthe MPEG (Moving Picture Experts Group) 2 method. The MPEG 2 method is apicture compression method adopted at a time of recording the videoinformation onto the DVD 1 in the present embodiment.

Here, the outline of the MPEG 2 method is explained. Namely, in general,frame pictures forward and backward of one frame picture in continuousframe pictures are often resembled to each other and have mutualrelationships. The MPEG 2 method is a method, which is proposed bypaying an attention to this fact, and which generates one frame pictureexisting between a plurality of frame pictures on the basis of theplurality of frame pictures transferred while they are timely separatedby a few or several frames from each other, by means of an interpolatingcalculation based on moving vectors etc. of the original picture. Inthis case, if this one frame picture is to be recorded, it is enough tojust record the information as for a differential vector and a movingvector thereof with respect to the plurality of frame pictures, so as toreproduce this one frame picture by estimating it from the plurality offrame pictures with referring to these vectors, at a time ofreproduction. By this, the compression recording is enabled with respectto the picture.

The MPEG 2 method used in the present embodiment employs a variable ratemethod, in which the data amount included in each COP is not constant.

In the above explained record format having a hierarchical structure asshown in FIG. 1, each division can be freely set according to theauthor's intention, so as to perform recording on the basis of these setdivisions. By performing the reproduction on the basis of a laterdescribed logical structure for each of these divisions, the variegatedreproduction can be performed.

Nextly, a logical format (logical structure) constructed by combiningthe information recorded by the physical divisions shown in FIG. 1 isexplained with reference to FIG. 2. The information is not actuallyrecorded on the DVD 1 in the logical structure of FIG. 2. Instead,information (e.g. access information or time information) to reproduceeach data shown in FIG. 1 by combining them (especially combining thecells 20) in the logical structure shown in FIG. 2, is recorded on theDVD 1, especially in the control data 11.

To make the explanation clear, the following explanation is made fromthe lower hierarchical layer in FIG. 2. One program 60 is logicallyconstructed on the basis of the author's intention by selecting andcombining a plurality of cells 20 among the physical structuresexplained by use of FIG. 1. The program 60 is also a minimum logicalunit, which division can be identified by a system controller of areproducing apparatus described later and which can be accessed by useof a command by the system controller. It is also possible for theauthor to define a gathering of one or more programs 60 as a minimumunit, which can be freely selected to be watched or listened to by theaudience and which is referred to as a PTT (ParT of Title).

Since one program 60 is logically constructed by selecting a pluralityof cells 20, it is possible to use one cell commonly for a plurality ofprograms 60, namely to perform a so-called “alternative usage” of thecell 20 in which one cell 20 is reproduced in a plurality of differentprograms 60.

Here, as for the number of each cell 20, at a time of treating the cell20 on the physical format shown in FIG. 1, the number is treated as thecell ID number (which is indicated by cell ID#in FIG. 1). On the otherhand, at a time of treating the cell 20 on the logical format shown inFIG. 2, the number is treated as the cell number in the order ofdescription in the PGCI described later.

Next, by combining a plurality of programs 60, one PGC (Program Chain)61 is logically constructed on the basis of the author's intention. Theaforementioned PGCI (ProGram Chain Information) is defined by a unit ofthe PGC 61. The PGCI includes information indicating: the reproductionorder of the cells 20 for each program 60 at a time of reproducing eachprogram 60 (by this reproduction order, a unique program number (#1, #2,. . . ) is assigned to each program 60); the reproduction order for eachcell 20 (by this reproduction order, a unique cell number is assigned toeach cell 20); an address which is a record position of each cell 20 onthe DVD 1; the number of the cell 20 positioned at the head of oneprogram 60 to be firstly reproduced; a reproduction method for eachprogram 60 [it is possible for the author to select one reproductionmethod for each PGC 61 out of (i) a random reproduction (which is arandom reproduction by use of random numbers, and the same program 60may be reproduced by a plurality of times), (ii) a shuffle reproduction(which is a random reproduction by use of random numbers in the samemanner as the random reproduction, but one program 60 is reproduced justonce but not reproduced by a plurality of times), (iii) a Loopreproduction (which is a reproduction to reproduce one PGC 61repeatedly), and (iv) a combination of the loop reproduction with therandom reproduction or the shuffle reproduction, as a reproductionmethod to be employed at a time of reproduction]; and various commands(e.g. commands able to be specified by the author for each PGC 61 oreach cell 20). The recording position of the PGCI on the DVD 1 may be inthe control data 11 as aforementioned, or in a control data (riotillustrated) in the video manager 2 if the pertinent PGCI is related tothe menu in the video manager 2 (refer to FIG. 1).

In one PGC 61, the substantial video and audio data etc. are included asa combination of the programs 60 (in other words, the combination of thecells 20) other than the above mentioned PGCI.

Further, in one PGC 61, it is possible to perform the alternative usageof the cell 20 as explained before in the explanation for the program 60(i.e. such a usage that the same cell 20 is commonly used by a pluralityof different PGC 61). As the method of reproducing the cell 20 to beused, the author can select a method of reproducing the cells 20 in anorder regardless of the recording order on the DVD 1 (i.e. the method ofreproducing the cells discontinuously arranged, for example, the methodof reproducing the cell 20 prior which is recorded posterior on therecord track) other than a method of reproducing the cell 20 in the,recording order on the record track on the DVD 1 as it is (i.e. themethod of reproducing the cells continuously arranged).

Then, one title 62 is logically constructed of one or a plurality ofPGCs 61 (PGC#1, PGC#2, . . . ) as shown in FIG. 2. The title 62 is, forexample, a unit corresponding to one movie, and is completed informationwhich the author would like to offer to the audience of the DVD 1.

Finally, one VTS 63 is logically constructed of one or a plurality oftitles 62 (title#1, title#2, . . . ) as shown in FIG. 2. The title 62included in the VTS 63 has the attributes common to each other. Forexample, the movies based on one movie hut in different languagescorrespond to the respective titles 62. The information included in oneVTS 63 shown in FIG. 2 corresponds to information included in one VTS 3shown in FIG. 1. Namely, all information included in the logical VTS 63shown in FIG. 2 is recorded as one VTS 3 in the DVD 1 shown in FIG. 1.

As the author specifies the information divided in the physicalstructure on the DVD 1 on the basis of the above described logicalformat, the video image (e.g. the movie image) for the audience to watchis to be formed.

In the explanations for the physical structure shown in FIG. 1, for theeasy understanding of the content, it has been explained such that aplurality of cells 20 are recorded in the order of the ID numbers.However, in the DVD 1 of the present embodiment, one cell 20 may bedivided into a plurality of interleaved units IU to be actually recordedon the DVD 1, as shown in FIG. 3.

Namely, as shown in FIG. 3, it is assumed that the author constructs onePGC 61A of the cells 20 having the ID numbers 1, 2 and 4, and constructsanother PGC 61B of the cells 20 having the ID numbers 1, 3 and 4. Inthis case, at a time of reproducing the information from the DVD 1 onthe basis of the PGC 61A, only the cells having the ID numbers 1, 2 and4 are reproduced, while, at a time of reproducing the information fromthe DVD 1 on the basis of the PGC 61B, only the cells 20 having the IDnumbers 1, 3 and 4 are reproduced. In the case of the PGC 61A forexample, if the cells 20 are recorded spaced from each other for each IDnumber, a certain time period to jump the optical pickup from the recordposition of the cell 20 having the ID number 2 on the DVD 1 to therecord position of the cell 20 having the ID number 4 on the DVD 1 isrequired in the reproduction. This results in that the continuousreproduction (hereinafter, it is referred to as a “seamlessreproduction”) of the cell 20 having the ID number 2 and the cell 20having the ID number 4 may not be possible depending on a capacity of atrack buffer of the reproducing apparatus described later.

Therefore, in the case shown in FIG. 3, the cell 20 having the ID number2 and the cell having the ID number 3 are divided into interleaved unitsIU and are recorded by the interleaved units IU, each having a length,which does not destroy the continuity of an output signal of the trackbuffer even if an input signal to the track buffer is temporarilystopped, in correspondence with an input and output processing speeds atthe track buffer (i.e. the interleaved units IU, each having a lengthwhich allows the track buffer to continuously output the output signaleven if the input signal to the track buffer is ceased while the opticalpickup jumps for the interval of one interleaved unit IU). For example,in case of reproduction based on the PGC 61A, only the interleaved unitsIU constructing the cell 20 corresponding to the ID number 2 arecontinuously detected to be reproduced. In the same manner, in case ofreproduction based on the PGC 61B, only the interleaved units IUconstructing the cell 20 corresponding to the ID number 3 arecontinuously detected to be reproduced. The length of the interleavedunit IU may be determined with considering the capability of a drivingmechanism such as a slider motor to perform the track jump, in additionto the memory capacity of the track buffer.

In this manner, by dividing one cell 20 into a plurality of interleavedunits IU and recording them according to the author's intention, thesignal outputted from the track buffer can be continuous even at a timeof reproducing the PGC 61 including the cells 20 having thediscontinuous ID numbers, so that it is possible for the audience towatch continuous reproduction video image.

Each interleaved unit IU is completed in one VOB 10, and does not strideover two adjacent VOBs 10. As for the relationship between theinterleaved unit IU and the VOB unit 30, one or a plurality of VOB units30 are included in one interleaved unit IU. One VOB unit 30 is completedin one interleaved unit IU, and is not divided into a plurality ofinterleaved units IU or does not strides over a plurality of interleavedunits IU.

Nextly, among the video information and the audio information having theabove mentioned physical structure and logical structure, the audio pack43 especially related to the present invention is explained in detailwith reference to FIGS. 4 and 11.

The audio information in the DVD of the present embodiment consists oflinear audio data based on the PCM (Pulse Code Modulation) method(hereinbelow, it is referred to as “PCM linear audio data”) having thespecification as listed below, for example.

Sampling frequency 48 kHz or 96 kHz the number of quantized bits 16bits. 20 bits or 24 bits channel number 1 ch to 8 ch

As a combination of the parameters in this specification, for example,if the combination of 96 kHz, 24 bits and 8 ch is considered, the datarate of the PCM linear audio data becomes 18.432 MHz (Mega Hz). In orderto perform the reproduction by this data rate, a significantly highoperation rate or speed is required to the reproducing apparatus and theelectric power consumption accompanying the rotation number of the diskis also significantly Large. Therefore, in the DVD 1 of the presentembodiment, with considering these operation rate and electric powerconsumption of the hardware of the reproducing apparatus, the upperlimit of the data rate of the audio data is set to 6.144 MHz. Thus, inthe DVD 1 of the present embodiment explained hereinbelow, the PCMlinear audio data is dealt with, which specification is as shown in atable of FIG. 4. In the table of FIG. 4, the expression of “48k 98k” ina column of the sampling frequency indicates that either one of 48 kHzand 96 kHz is available (the same thing can be said for the rest), whilethe expression of “16, 20, 24” in the column of the number of quantizedbits indicates that either one of 16 bits. 20 bits and 24 bits isavailable (the same thing can be said for the rest).

Here, some examples of the arrangement of the PCM linear audio data areshown in FIGS. 5 to 7, respectively.

FIG. 5 shows the arrangement of sample data 301 a in the 16 bits mode,FIG. 6 shows the arrangement of sample data 301 b in the 20 bits mode,and FIG. 7 shows the arrangement of sample data 301 c in the 24 bitsmode.

In FIG. 5, sample data S2 n and Sn−1 respectively indicate the sampledata, which sample order is 2n, and the sample data, which sample orderis 2n−1 (n=0, 1, 2, . . . , and so forth on). Namely, each of dataportions A2 n, B2 n, . . . constructing sample data 302 a in the figureindicates 16 bits of respective one of the channels.

In FIG. 6, sample data S2 n and S2 n−1 respectively indicate upper 16bits of the sample data, which sample order is 2n, and upper 16 bits ofthe sample data, which sample order is 2n−1. Sample data e2 n and e2 n−1respectively indicate lower 4 bits of the sample-data, which sampleorder is 2n, and lower 4 bits of the sample data, which sample order is2n−1. Namely, each of data portions A2 n, B2 n, constructing sample data302 b in the figure indicates the upper 16 hits of respective one of thechannels, while each of data portions a2 n, b2 n, . . . constructingsample data 303 b in the figure indicates the lower 4 bits of respectiveone of the channels.

In FIG. 7, sample data S2 n and S2 n−1 respectively indicate upper 16bits of the sample data, which sample order is 2n, and upper 16 bits ofthe sample data, which sample order is 2n−1. Sample data e2 n and e2 n−1respectively indicate lower 8 bits of the sample data, which sampleorder is 2n, and lower 8 bits of the sample data, which sample order is2n−1. Namely, each of data portions A2 n, B2 n, . . . constructing thesample data 302 c in the figure indicates the upper 16 bits ofrespective one of the channels, while each of data portions a2 n, b2 n,. . . constructing the sample data 303 c in the figure indicates thelower 8 bits of respective one of the channels.

Either one of the data 301 a, the data 301 b and the data 301 c ofrespective modes shown in FIG. 5 to FIG. 7 is treated as one unit forevery 2 samples corresponding to the number of channels.

The PCM linear audio data having the above explained specification ismodified or arranged into the MPEG 2 system stream in accordance withthe ISO IEC13818-1 standard. Namely, according to this standard, the PCMlinear audio data is divided into data pieces each having such a lengthable to be stored in one audio pack 43 shown in FIG. 1, and the divideddata pieces are stored recorded) in respective audio packs 43.

In this case, one audio pack 43 has a size of not more than 2048 bytes,for example, as shown in FIG. 8, and has one packet in one pack. Moreconcretely, in FIG. 8, the audio pack 43 has: a pack header 201 of 14bytes, which indicates the attribute information as for the whole of thepertinent audio pack, e.g. information indicating that the PCM linearaudio data in the pertinent audio pack is based on the MPEG 2 systemstream standard; and a packet 202 of 2034 bytes, in which thesubstantial PCM linear audio data is stored.

Then, the packet 202 is provided with: a packet header 203 indicatingthe attribute information as for the whole of the pertinent packet; asub stream ID; audio frame information 205; audio data information 206;and the PCM Linear audio data 207 of 2013 bytes, which is thesubstantial audio data pieces.

The maximum number of the audio samples, which can be stored in eachaudio pack 43 (packet 202) constructed in the above mentioned manner, isindicated in a table of FIG. 9, as for respective combinations shown inFIG. 4. As understood from the table of FIG. 9, since the number of theaudio samples is treated in the unit of 2 samples (refer to FIGS. 5 to7), the maximum number of the samples able to be stored in one packet202 is always even.

Nextly, the data structure of the packet header 203 is explained in moredetail with reference to FIG. 10.

In FIG. 10, the packet header 203 is provided with: a packet start codefield 203 a of 3 bytes indicating the start position of the pertinentpacket; a stream ID field 203 b indicating that the audio data is basedon the standard of the private stream 1; and a packet length field 203 cindicating the length of the pertinent packet.

The packet header 203 especially includes a PTS (Presentation Time Stampi.e. time management information for the reproduction output) field 203f, to which the PTS indicating the time to manage the timing of thereproduction output set to synchronize each audio stream is written.This PTS field 203 f is added to the packet header 203 only if the headof the audio frame is located in the pertinent packet 202. On thecontrary, if the head of the audio frame is not located in the pertinentpacket 202, the PTS field 203 f is not added, and that the space forthis PTS field 203 f is packed by the subsequent data as forwardpacking. Therefore, the number of bytes of this packet header 203 isvariable depending upon the existence and non-existence of the PTS 203f. Further, if there are two heads of the audio frames are located inone packet 202, only the PTS corresponding to the first audio frameamong these is added to the packet header 203. The PTS indicates thetime, at which the head byte of the audio frame appeared in thepertinent packet is to be outputted from the decoder. The PTS isspecified by a unit of 90 kHz and by a length of 33 bits. The reason foradopting 90 kHz here is that it is a value of the common multiple of thefrequencies of audio frames such as the NTSC (National Television SystemCommittee) method, the PAL (Phase Alternation Line) method and the Like.The reason for adopting 33 bits here is to express the time in the rangeof 24 hours in one day by the measurement of the 90 kHz clock.

The packet header 203 is further provided with: a PTS and DTS flag field203 d, which indicates a PTS flag indicating whether or not the PTS isadded in the pertinent packet header 203; a field 203 e indicating thedata length of the header; a field 203 g indicating the buffer scalewhich is required for the reproduction: and a field 203 h indicating thebuffer size.

Finally, the packet header 203 is provided with a stuffing bytes field203 i of variable Length from 1 to 7 bytes, such that the stuffing byteOr bytes are stuffed (packed) so as to make the byte length of thepertinent audio pack 43 be equal to a predetermined byte length, whichis not longer than 2048 bytes, as the occasion demands. Each stuffingbyte has a special value such as “FFh”, for example, so that it is easyto cut reading this field 203 i by recognizing the pattern of thestuffing byte.

Nextly, the data structures of the sub stream ID 204, the audio frameinformation 205 and the audio data information 206, which are positionednext to the packet header 203 in the private data area of the packet 202shown in FIG. 8, are explained in more detail with reference to FIG. 11.

In FIG. 11, in the private data area of the packet 202, there areprovided with: the sub stream ID 204 of 1 byte, which indicates that theaudio data in the pertinent packet is the PCM linear audio data recordedunder the standard of the private stream 1; the audio frame information205 of 3 bytes, which includes information indicating the number offrame boundaries (i.e. the number of frame headers) within the pertinentpacket, and a pointer indicating the position of a first access unit:the audio data information 206 of 3 bytes indicating various parametersrelated to the linear audio such as an audio emphasis flag, an audiomute flag, an audio frame number which boundary is firstly appeared inthe pertinent packet, the number of quantized bits, a samplingfrequency, a number of channels and a dynamic range; and the PCM linearaudio data 207 of 2013 bytes at the maximum, as the substantial audiodata pieces.

As described above, the area, where the PCM linear audio data can bestored in one audio pack 43, is 2013 bytes at the maximum.

In the present embodiment, the frequency of the audio frame is setespecially to satisfy three conditions as listed below.

-   Condition [C1] It is 1/n (n: natural number) 48 kHz and 96 kHz,    which are the sampling frequencies.-   Condition [C2] It is 1/n (n: natural number) of 90 kHz, which is the    frequency used for specifying the PTS.-   Condition [C3] It is higher than 387 Hz, which is the highest    frequency of the audio pack 43 under the specification shown in the    table of FIG. 4.

The above mentioned condition [C1] is a condition not to discontinue theaudio frame while sampling. The above mentioned condition [C2] is acondition not to degrade the accuracy of the PTS. The above mentionedcondition [C3] is a condition to add the PTS into the packet 202 as forall of the audio packs 43. The “highest frequency” mentioned in thecondition [C3] is a frequency in case of the combination of 48 kHz, 8 chand 16 bits as the specification of the audio data, in which the maximumnumber of the samples in the packet is the minimum (124 samples) in thetable of FIG. 9, and is obtained by 1. {124×(1/48 kHz)}=387 Hz.

At first, from the conditions [C1] and [C2], the frequency of the audioframe must be 1/n (n: natural number) of 6000, which is the greatestcommon divisor of 48000 and 90000. Then, with considering the condition[C3] in addition, the frequency of the audio frame to be obtained inthis case is either one of 600 Hz, 750 Hz, 1200 Hz, 1500 Hz, 3000 Hz and6000 Hz.

Here, since the number of bits of an audio frame counter required forthe reproducing apparatus is increased in proportional to the frequencyof the audio frame, the treatment of the audio data becomes moredifficult or troublesome as the frequency gets higher. From this pointof view, the desirable frequency among the above obtained audiofrequencies is 600 Hz, which is the lowest frequency among those. Atthis time, the reproduction time period of one audio frame is 1 600Hz≈1.67 ms, so that a relatively simple reproduction is possible.

In this manner, according to the present embodiment, since the frequencyof the audio frame is prescribed to be 600 Hz etc., and since thehighest frequency of the audio pack 43 corresponding to the table shownin FIG. 4 is 387 Hz, the PTS is always added to any one of the packetheaders 203. In this way, since the PTS is always added to any one ofthe packet headers 203, the aforementioned PTS flag is always set to ON,so that the PTS flag in the present embodiment is for the confirmationpurpose only, and there is no essential problem even if this PTS flag isnot added thereto.

As a result of the above, according to the present embodiment, since thePTS is always added to any one of the packet headers 203 which areincluded in respective audio packs 43, such a problem is never causedthat, because the PTS randomly exists or rot exists in the packerheaders 203, the position of the data after the PTS is shifted one byone in a random or unknown manner. Thus, it is possible to cut readingthe data of the bytes in the constant number (e.g. 17 bytes from thehead of the packet header) in the packet data 203 shown in FIG. 10, andto read the stream ID 204, the audio frame information 205 and the audiodata information 206 shown in FIG. 11 which are mainly required forreproducing the PCK linear audio data, after reading the stuffing bytes203 i in the predetermined number of bytes, which reading can be easilycut by the aforementioned pattern recognition, by use of a rather simplealgorithm, while reducing the cost of the reproducing apparatus andsimplifying the reproducing apparatus.

This advantage of the present embodiment is evaluated by assuming a casewhere the frequency of the audio pack 43 is 387 Hz and that thefrequency of the audio frame is 75 kHz in the same manner as theaforementioned conventional CD. In this case, since 387 Hz 75 Hz=5.16,the boundary (i.e. the head) of the audio frame appears once every 5 to6 audio packs. Namely, the PTS is added to the audio pack once every 5to 6 audio packs. As a result, such a situation is caused that the PTSrandomly exists and not exists in the respective packet headers of theaudio packs, so that the position of the data after the PTS is shiftedone by one in a random or unknown manner, which is a problem. In thiscase, although it is possible to judge the existence and non existenceof the PTS by referring to the aforementioned PTS flag provided in thepacket header, a very Complicated algorithm is necessary in thereproducing apparatus in any event, in order to cut reading the data ofthe bytes in the constant number as aforementioned.

As described above, the present embodiment is quite advantageous ascompared with the comparison example in which the frequency of the audioframe same as the case of the conventional Cl) is used for the DVD inthe present embodiment.

In the present embodiment, the video data stored in the video pack 42 inFIG. 1 is based on one of the NTSC method, PAL method and the Hi-Visionmethod.

The frequencies of the video frames based on these methods are as listedbelow.

NTSC 29.97 (= 30 1.001) Hz PAL (SECOM) 25 Hz Hi-Vision 30 Hz

Here, it is preferable in the present embodiment that the frequency ofthe audio frame satisfies a condition [C4] as following in addition tothe aforementioned conditions [C1] to [C3].

Condition [C4] It is a frequency equal to the integer multiple of theleast common multiple of the frequencies of the existing video frames ofvarious kinds.

In this condition [C4], the “least common multiple” is 30000, which isthe least common multiple of 29.97, 25 and 30. Thus, the integermultiple of this least common multiple cannot satisfy the aforementionedconditions [C] and [C2]. Therefore, as a second best stringer, withconsidering the fact that 29.97 and 30 are different from each other byonly about 0.001%, the frequency which is the integer multiple of 150,which is the least common multiple of 30 and 25, is treated as thefrequency “equal to the integer multiple of the Least common multiple”in the condition [C4].

Here, either one of the aforementioned audio frequencies 600 Hz, 750 Hz,1200 Hz, 1500 Hz, 3000 Hz and 6000 Hz obtained by the conditions [C1] to[C3], satisfies this condition [C4].

As a result, in the present embodiment, the compatibility orcongeniality in the frequency between the audio frame and the videoframe is excellent. Especially in case of the PAL (SECOM) or the HiVision, the video frames are perfectly synchronized with the audioframes. In case of the NTSC, the video frames are almost synchronizedwith the audio frames. For this reason, with respect to the dataarrangement in the physical data structure shown in FIG. 1, it ispossible to make the audio information in the data amount of one audioframe and the video information in the data amount of one video framecorrespond to the time period almost coincident to each other.Consequently, a complicated signal process for compensating thedifference in the reproduction time between the audio information andthe video information at the time of recording, editing and reproducingis not necessary, which is another advantage of the present embodiment.In this manner, the present embodiment is quite advantageous as comparedwith a comparison case, where 75 Hz is employed as the frequency of theaudio frame same as the conventional CD, and the synchronization of theaudio data with the video data based on the NTSC method or the Hi Visionmethod, except for the PAL (SECOM) method, cannot be achieved at all, sothat the complicated signal process is required.

Since the DVD has such a large memory capacity that, in addition to onemovie, the audio voices and captions (titles) in a plurality of kinds oflanguages corresponding to this one movie can be recorded on a singleoptical disk, it is effective to apply the above described record formatespecially to the DVD 1.

(II) Embodiment of Recording Apparatus

Next, an embodiment of recording apparatus for recording the abovementioned control information, video information and audio informationonto the DVD 1 will be explained with reference to FIG. 12.

At first, a construction and an operation of the recording apparatus asthe embodiment is explained with reference to FIG. 12.

As shown in FIG. 12, a recording apparatus St as the present embodimentis provided with: a VTR (Video Tape Recorder) 70; a memory 71; a signalprocess unit 71; a hard disk (HD) device 73; a hard disk (HD) device 74;a controller 75; a multiplexer 76; a modulator 77; and a masteringdevice 78.

Nextly, an operation of the present embodiment is explained.

Record information R, which is a raw material such as audio information,video information etc. to be recorded on the DVD 1, is temporarilyrecorded in the VTR 70. Then, the record information R temporarilyrecord in the VTR 70 is outputted to the signal process unit 72 by arequest from the signal process unit 72.

The signal process unit 72 applies an A/D (Analog to Digital) convertingprocess and a signal compressing process to the record information Routputted from the VTR 70, and time-axis multiplexes the audioinformation and the video information to output it as a compressedmultiplexed signal Sr. After that, the compressed multiplexed signal Sroutputted therefrom is temporarily stored into the hard disk device 73.

Along with this, the memory 71 classifies the record information R intoa plurality of partial record information Pr in advance, and temporarilystores content information related to the partial record information Prwhich is inputted beforehand on the basis of a cue sheet ST, on whichthe user defined information such as the packet header, the sub streamID, the audio frame information. the audio data information and so onshown in FIGS. 10 and 11, are written. Then, the memory 71 outputs it asa content information signal S1 on the basis of a request from thesignal process unit 72.

Then, the signal process unit 72 generates and outputs a PCI informationsignal Spci and a DSI information signal Sdsi corresponding to thepartial record information Pr with referring to a time code Tt, on thebasis of the time code Tt corresponding to the record information Routputted from the VTR 70 and the content information signal Sioutputted from the memory 71. Then, the PCI information signal Spci andthe DSI information signal Sdsi are temporarily stored in the hard diskdevice 74.

The above described processes are performed with respect to the wholerecord information R.

When the above described processes are finished as for the whole recordinformation R, the controller 75 reads out the compressed multiplexedsignal Sr from the hard disk device 73, reads out the PCI data signalSpci and the DS1 data signal Sdsi as well as other control informationsfrom the hard disk device 74, generates additional information DA, whichincludes independently each of the PCI data 50, the DSI data 51 and theother control informations, on the basis of these read out signals, andtemporarily stores the additional information DA into the hard diskdevice 74. This Ls because there may be control information, whichcontent is determined in dependence upon a generation result of thecompressed multiplexed signal Sr among various control informations.

On the other hand, the controller 75 performs a time management for eachof the operations of the signal process unit 72, the hard disk device 73and the hard disk device 74, and reads out the additional informationDA, which includes the PCI information signal Spci and the DSIinformation signal Sdsi, from the hard disk device 74, so that thecontroller 75 generates and outputs an additional information signal Sacorresponding to the read out additional information DA, and generatesand outputs an information selection signal Scc to time axis-multiplexthe compressed multiplexed signal Sr and the additional informationsignal Sa.

After that, the compressed multiplexed signal Sr and the additionalinformation signal Sa are time-axis multiplexed by the multiplexer 76 tobe outputted as an information added compressed multiplexed Sap. Ifthere exists the sub picture information to be recorded, it is inputted,by other means such as a hard disk device not illustrated, to the signalprocess unit 72, so that it is processed in the same manner as the videoand audio information thereat.

Then, the modulator 77 adds an error correction code (ECC), such as aReed Solomon code, and applies a modulation such as an eight to sixteen(8-16) modulation with respect to the information added compressedmultiplexed signal Sap outputted from the multiplexer 76, and generatesand outputs a disk record signal Sm to the mastering device 78.

Finally, the mastering device 78 records the disk record signal Sm to astamper disk, which becomes a master (i.e. a cutting dye) for theproduction of an optical disk. Then, by use of this stamper disk, anoptical disk as a replica disk, which can be on sale in the generalmarket, i.e. the DVD 1, can be produced by a replication device notillustrated.

Nextly, the processes of recording the audio information and the videoinformation into the audio pack and the video pack respectively relatedto the present embodiment are explained in more detail.

In the above explained recording processes, the signal process unit 72especially performs a process of dividing and compressing the videoinformation, and stores (packs) the divided and compressed videoinformation into the video pack 42 shown in FIG. 1. The signal processunit 72 also performs a process of dividing the audio information andarranging the divided audio information to a predetermined sample dataarrangement, and stores (packs) the divided and arranged audioinformation into the audio pack 43 shown in FIGS. 1 and 8. Then, thesignal process unit 72 time axis multiplexes these video pack 42 and theaudio pack 44, and outputs the multiplexed packs as the compressedmultiplexed signal Sr.

At this time, the audio information stored or packed in the audio pack43 is the aforementioned PCX linear audio data as shown in the table ofFIG. 4. And that, the frequency of the audio frame thereof is either oneof 600 Hz, 750 Hz, 1200 Hz, 1500 Hz, 3000 Hz and 6000 Hz, while thefrequency of the audio pack 43 is 387 Hz at the maximum.

As a result of the above, in the DVD recorded by the informationrecording apparatus St, the PTS is always added to any one of theaforementioned packet headers. Therefore, in the information reproducingapparatus for reproducing this DVD, it is possible to cut reading thedata of the bytes in the constant number in the packet header, and toread the stream ID, the audio frame information and the audio datainformation which are mainly required for reproducing the PCM linearaudio data, by use of a rather simple algorithm, while simplifying theconstruction of the information reproducing apparatus. On the contrary,on the side of the information recording apparatus S2, since the PTS isalways added to each of the packet headers, it is not necessary toperform a complicated process e.g. a process of forward packing thesubsequent data of the possibly existing PTS in dependence upon theexistence and non existence of the PTS, and it is further possible tosimplify the process of adding the PTS flag, which is always set to ON.Furthermore, the video information stored or packed in the video pack 42by the signal process unit 72 is the video data based on either one ofthe NTSC, PAL and Hi-Vision methods as aforementioned.

As a result, in the DVD recorded by the information recording apparatusS1, the compatibility or congeniality in the frequency between the audioframe and the video frame is excellent. Thus, a complicated signalprocess for compensating the difference in the reproduction time betweenthe audio information and the video information is not necessary on theside of the information recording apparatus S1 as well as on the side ofthe information reproducing apparatus, which is another advantage of thepresent embodiment.

(III) Embodiment of Reproducing Apparatus

Next, an embodiment of reproducing apparatus for reproducing theinformation recorded on the DVD by the above mentioned recordingapparatus S1 will be explained with reference to FIG. 13.

At first, a construction and an operation of the reproducing apparatusas the embodiment is explained with reference to FIG. 13.

As shown in FIG. 13, a reproducing apparatus S2 as the presentembodiment is provided with: an optical pickup 80; a demodulate andcorrect unit 81; stream switches 82 and 84; a track buffer 83; a systembuffer 85; a demultiplexer 86; a VBV (Video Buffer Verifier) buffer 87;a video decoder 88; a sub picture buffer 89; a sub picture decoder 90; amixer 91; an audio buffer 92; an audio decoder 93; a PCI (PresentationControl Information) buffer 94; a PCI decoder 95; a high light buffer96; a high light decoder 97; an input unit 98; a display unit 99; asystem controller 100; a drive controller 101; a spindle motor 102; anda slider motor 103. The construction shown in FIG. 13 only illustratesthe portions related to the video and audio reproduction of thereproducing apparatus S2. The description and the detailed explanationas for servo circuits to servo control the optical pickup 80, thespindle motor 102, the slider motor 103 and the like are omitted sincethey are constructed in the same manner as the conventional arts.

Nextly, an overall operation of the present embodiment LS explained.

The optical pickup 80 includes a laser diode, a polarization beamsplitter, an objective lens, a photo-detector and the like notillustrated, and irradiates a light beam B as a reproduction light withrespect to the DVD 1. The optical pickup 80 receives a reflection lightof the light beam B from the DVD 1, and outputs a detection signal Spcorresponding to information pits formed on the DVD 1. At this time, thetracking servo control and the focus servo Control are operated withrespect to the objective lens etc. of the optical pickup 80 in the samemanner as the conventional art so that the light beam B can beirradiated precisely onto the information track of the DVD 1 and thatthe light beam B can be focused on the information record surface of theDVD 1.

The detection signal Sp outputted from the optical pickup 80 is inputtedto the demodulate and correct unit 81, where a signal demodulationprocess and an error correct process are applied to it to generate ademodulation signal Sdm, which is outputted to the stream switch 82 andthe system buffer 85.

The opening and closing operation of the stream switch 82, to which thedemodulation signal Sdm is inputted, is controlled by a switch signalSsw1 from the drive controller 101. When it is closed, the stream switch82 passes therethrough the inputted demodulation signal Sdm as it is tothe track buffer 83. When it is opened, the demodulation signal Sdm isnot outputted therethrough, so that unnecessary or useless information(signal) is not inputted to the track buffer 83.

The track buffer 83, to which the demodulation signal Sdm is inputted,consists of a FIFO (First In First Out) memory, for example. The trackbuffer 83 temporarily stores the inputted demodulation signal Sdm, andcontinuously outputs the stored demodulation signal Sdm when the streamswitch 84 is closed. The crack buffer 83 compensates a difference orfluctuation in the data amount between respective GOP under the MPEG 2method, and continuously outputs the demodulation signal Sdm, which isdiscontinuously inputted due to a track jump in the aforementionedseamless reproduction, in case of reading the data divided into theinterleaved units IU, so as to avoid the interruption of thereproduction due to the discontinuity.

The opening and closing operation of the stream switch 84, to which thedemodulation signal Sdm is continuously inputted, is controlled by aswitch signal Ssw2 from the system controller 100 such that the variousbuffers at its posterior stage may not be over flown or, on thecontrary, may not become empty to stop the decoding process, in theseparating process by the demultiplexer 86.

On the other hand, the system buffer 85, to which the demodulationsignal Sdm is inputted in parallel with the track buffer 83, accumulatesthe management information (e.g. the video manager 2), the control data11 of the VTS 3 and the like (refer to FIG. 1) which are detectedfirstly upon loading the DVD 1 and which are related to the wholeinformation recorded on the DVD 1. Then, the system buffer 85 outputsthe accumulated data as a control information Sc to the systemcontroller 100, and temporarily stores the DSI packet 51 for each navipack 41 (refer to FIG. 1) as the occasion demands while reproducing theinformation, to output it also as the control information Sc.

The demultiplexer 86, to which the demodulation signal Sdm iscontinuously inputted through the stream switch 84, separates the videoinformation, the audio information, the sub picture information and thePCI packet 50 for each navi pack 41 respectively from the inputteddemodulation signal Sdm, and outputs them as a video signal Sv, a subpicture signal Ssp, an audio signal Sad and a PCI signal Spcrespectively to the VBV buffer 87, the sub picture buffer 89, the audiobuffer 92 and the PCI buffer 94. The demultiplexer 86 sends the packetheader etc. of each packet as the control signal Sdmx to the systemcontroller 100. There may be a case where, in tie demodulation signalSdm, different streams of the audio information or the sub pictureinformation in a plurality of different languages are included as theaudio or sub picture information. In that case, a desirable language isselected for the audio or sub picture information by a stream selectionsignal Slc from the system controller 100, so that the audio or subpicture information in the desirable language is outputted to the audiobuffer 92 or the sub picture buffer 89.

The VBV buffer 87, to which the video signal Sv is inputted, consists ofa FIFO memory, for example. The VBV buffer 87 temporarily stores thevideo signal Sv and outputs it to the video decoder 88. The VBV buffer87 compensates the difference or fluctuation in the data amount betweenrespective pictures of the video signal Sv compressed by the MPEG 2method. Then, the video signal Sv in which the differences in the dataamount are compensated, is outputted to the video decoder 88, and isdecoded by the MPEG 2 method to be outputted as a decoded video signalSvd to the mixer 91.

On the other hand, the sub picture buffer 89, to which the sub picturesignal Ssp is inputted, temporarily stores the inputted sub picturesignal Ssp, and outputs it to the sub picture decoder 90. The subpicture buffer 89 is to synchronize the sub picture information includedin the sub picture signal Ssp with the video information correspondingto the sub picture information, and to output it. Then, the sub picturesignal Ssp synchronized with the video information is inputted to thesub picture decoder 90 and is decoded to be outputted as a decoded subpicture signal Sspd to the mixer 91.

In a case where the sub picture signal Ssp includes video information toconstruct a frame, a selection button etc. for displaying the menupicture plane, the sub picture decoder 90 changes a display condition ofthe selection button etc. to be displayed, in the sub picture signalSspd on the basis of a high light control information Sch from thesystem controller 100 to output it.

The decoded video signal Svd outputted from the video decoder 88 and thedecoded sub picture signal Sspd outputted from the sub picture decoder90 (which is in synchronization with the corresponding decoded videosignal Svd) are mixed together by the mixer 91, and are outputted as afinal video signal Svp to be displayed to a display device such as a CRT(Cathode Ray Tube) device not illustrated.

The audio buffer 92, to which the audio signal Sad is inputted, consistsof a FIFO memory, for example. The audio buffer 92 temporarily storesthe audio signal Sad and outputs it to the audio decoder 93. The audiobuffer 92 is to synchronize the audio signal Sad with the video signalSv or the sub picture signal Ssp including the corresponding videoinformation, and delays the audio signal Sad in accordance with theOutput condition of the corresponding video information. Then, the audiosignal Sad, which is time adjusted to synchronize with the correspondingvideo information, is outputted to the audio decoder 93. Then, apredetermined decoding process is applied thereat to the audio signalSad, and it is outputted as a decoded audio signal Sadd to a speakeretc. not illustrated. If it is detected by the system controller 100that it is necessary to temporarily stop (pause) the audio voice in thereproduction immediately after accessing, a pause signal Sca isoutputted from the system controller 100 to the audio decoder 93, sothat the output of the decoded audio signal Sadd is stopped temporarilyat the audio decoder 93.

The PCI buffer 94, to which the PCI signal Spc is inputted, consists ofa FIFO memory, for example. The PCI buffer 94 temporarily stores theinputted PCI signal Spc and outputs it to the PCI decoder 95. The PCIbuffer 94 is to synchronize the PCI packet 50, which is included in thePCI signal Spc, with the video information, the audio information andthe sub picture information corresponding to the PCI packet 50, andapply the PCI packet 50 to the video information and the like. Then,from the PCI signal Spc, which is synchronized with the correspondingthe video information and the like by the PCI buffer 94, a high tightinformation included in the PCI packet 50 is separated or extracted bythe PCI decoder 95, and is outputted as a high light signal Shi to thehigh light buffer 96. The portion of the PCI packet 50 other than thehigh light information is outputted as a PCI information signal Spci tothe system controller 100.

The high light buffer 96, to which the high light signal Shi isinputted, consists of a FIFO memory, for example. The high light buffer96 temporarily stores the inputted high light signal Shi and outputs itto the high light decoder 97. The high light buffer 96 is to timecompensate the high light signal Shi so as to precisely perform a changein the display condition of the selection item, which corresponds to thehigh light information, in correspondence with the sub picture signalSsp which includes the video information for the high light information.Then, the time compensated high light signal Shi is decoded by the highlight decoder 97, and the information included in the high light signalShi is outputted as a decoded high light signal Shid to the systemcontroller 100. Here, the system controller 100 outputs theaforementioned high light control signal Sch to change the displaycondition by the high light information, on the basis of the decodedhigh light signal Shid.

On the basis of the control information Sc inputted from the systembuffer 85, the control signal Sdmx inputted from the demultiplexer 86,the PCI information signal Spci inputted from the PCI decoder 95 and aninput signal Sin inputted from the input unit 98 such as a remotecontroller, the system controller 100 outputs the aforementioned switchsignal Ssw2, the language select ion signal Slc, the pause signal Scaand the high light control signal Sch to correctly perform thereproduction corresponding to those input signals, and also outputs adisplay signal Sdp to display an operation condition etc. of thereproducing apparatus S2 to the display unit 99 such as the liquidcrystal device.

Further, the system controller 100 outputs a seamless control signalScs1 corresponding to the track jump process such as a search processetc. to the drive controller 101, when it detects by the control signalSc or the aforementioned DSI data etc. that it is necessary to performthe track jump process such as a search in order to perform the seamlessreproduction.

Then, the drive controller 101, to which the seamless control signalScs1 is inputted, outputs a drive signal Sd to the spindle motor 102 orthe slider motor 103. By this drive signal Sd, the spindle motor 102 orthe slider motor 103 moves the optical pickup 80 such that the recordposition to be reproduced on the DVD 1 is irradiated with the light beamB (refer to an arrow of a broken line in FIG. 13), and the spindle motor102 CLV controls (Constant Linear Velocity controls) the rotation numberof the DVD 1. Along with this, the drive controller 101 outputs theaforementioned switch signal Ssw1 on the basis of the seamless controlsignal Scs1, so as to open the stream switch 82 when the demodulationsignal Sdm is not outputted from the demodulate and correct unit 81while the optical pickup 80 is being moved, and so as to close thestream switch 82 when the demodulation signal Sdm is started to beoutputted, so that the demodulation signal Sdm is outputted to the trackbuffer 83.

Nextly, the process of reproducing the audio information and the videoinformation respectively stored or packed in the audio pack and thevideo pack especially related to the present embodiment is explained inmore detail.

In the above explained reproducing processes, the demultiplexer 86outputs the video signal Sv, as the video information stored or packedin the video pack 42 divided as shown in FIG. 1, to the VBV buffer 87,and outputs the audio signal Sad, as the audio information stored orpacked in the audio pack 44 divided as shown in FIG. 1, to the audiobuffer 92.

At this time, the audio information stored or packed in the audio pack43 is the aforementioned PCM linear audio data as shown in the table ofFIG. 4. And that, the frequency of the audio frame thereof is either oneof 600 Hz, 750 Hz, 1200 Hz, 1500 Hz, 3000 Hz and 6000 Hz, while thefrequency of the audio pack 43 is 387 Hz at the maximum. Further, thevideo information stored or packed in the video pack 42 is the videodata based on either one of the NTSC. PAL and Hi-Vision methods asaforementioned.

Accordingly, the compatibility or congeniality in the frequency betweenthe audio frame of the audio signal Sad and the video frame of the videosignal Sv sequentially outputted from the demultiplexer 86 is excellent.Therefore, the aforementioned process of outputting the audio signal Sadin synchronization with the video signal Sv including the correspondingvideo information, by the audio buffer 92, is quite simple.

Further, the PTS is always added to each of the aforementioned packetheaders in the audio signal Sad inputted to the audio decoder 93. As aresult, in the audio decoder 93, it is possible to cut reading the dataof the bytes in the constant number in the packet header (e.g. 17 bytesfrom the head of the packet header), and to read the stream ID, theaudio frame information and the audio data information which are mainlyrequired for reproducing the PCM linear audio data after reading thestuffing bytes 203 i in the predetermined number of bytes, which readingcan be easily cut by the aforementioned pattern recognition, by use of arather simple algorithm.

As described above in detail, according to the present embodiment, thehardware construction as well as the algorithm as for the audio buffer92, the audio decoder 93 and the like can be simplified.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in alt respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

1. A computer-readable medium encoded with computer executableinstructions, comprising: audio information which comprises a pluralityof audio units, sampled by a predetermined sampling frequency andquantized by a predetermined quantization bit; and time managementinformation indicating a presentation time, by a predeterminedspecification frequency, at which the audio information is to bereproduced, wherein a frequency of the audio unit is 1/n (n: naturalnumber) of the sampling frequency and 1/m (m: natural number) of thespecification frequency.
 2. The information recording medium accordingto claim 1, wherein the sampling frequency is selected from a pluralityof sampling frequencies, and the quantization bit is selected from aplurality of quantization bits.
 3. The information recording mediumaccording to claim 1, wherein the audio information has a predeterminednumber of audio channels.
 4. The information recording medium accordingto claim 1, wherein the sampling frequency is selected from a pluralityof sampling frequencies, and the quantization bit is selected from aplurality of quantization bits, wherein the audio information has apredetermined number of audio channels, and wherein a plurality ofcombination of the sampling frequency, the quantization bit and thenumber of audio channels are defined in order for a data rate of theaudio information to be less than a predetermined value.
 5. Theinformation recording medium according to claim 1, wherein the audioinformation is divided into a plurality of audio packets, each includingthe time management information.
 6. The information recording mediumaccording to claim 5, wherein the time management information indicatesthe presentation time at which the audio information in thecorresponding audio packet is to be reproduced.
 7. The informationrecording medium according to claim 5, wherein each of the audio packetscomprises a header portion which includes the time managementinformation.
 8. The information recording medium according to claim 7,wherein the time management information indicates the presentation timeat which a first audio unit having a head portion in the correspondingaudio packet is to be reproduced.
 9. The information recording mediumaccording to claim 1, further comprising video information including aplurality of video units, wherein the frequency of the audio unit issubstantially equal to an integer multiple of a frequency of the videounit.
 10. The information recording medium according to claim 9, whereinthere are a plurality of different kinds of frequencies as the frequencyof the video unit, and the frequency of the audio unit is substantiallyequal to an integer multiple of a least common multiple of the differentkinds of frequencies.
 11. An information recording apparatus comprising:an audio processing device which generates audio information whichcomprises a plurality of audio units, sampled by a predeterminedsampling frequency and quantized by a predetermined quantization bit; amanagement information generating device which generates time managementinformation indicating a presentation time, by a predeterminedspecification frequency, at which the audio information is to bereproduced; and a recording device which records the audio informationand the time management information on a recording medium, wherein afrequency of the audio unit is 1/n (n: natural number) of the samplingfrequency and 1/m (in: natural number) of the specification frequency.12. The information recording apparatus according to claim 11, whereinthe sampling frequency is selected from a plurality of samplingfrequencies, and the quantization bit is selected from a plurality ofquantization bits.
 13. The information recording apparatus according toclaim 11, wherein the audio information has a predetermined number ofaudio channels.
 14. The information recording apparatus according toclaim 11, wherein the sampling frequency is selected from a plurality ofsampling frequencies, and the quantization bit is selected from aplurality of quantization bits, wherein the audio information haspredetermined number of audio channels, and wherein a plurality ofcombination of the sampling frequency, the quantization bit and thenumber of audio channels are defined in order for a data rate of theaudio information to be less than a predetermined value.
 15. Theinformation recording apparatus according to claim 11, wherein the audioinformation is divided into a plurality of audio packets, each includingthe time management information.
 16. The information recording apparatusaccording to claim 15, wherein the time management information indicatesthe presentation time at which the audio information in thecorresponding audio packet is to be reproduced.
 17. The informationrecording apparatus according to claim 15, wherein each of the audiopackets comprises a header portion which includes the time managementinformation.
 18. The information recording apparatus according to claim17, wherein the time management information indicates the presentationtime at which a first audio unit having a head portion in thecorresponding audio packet is to be reproduced.
 19. The informationrecording apparatus according to claim 11, further comprising a videoprocessing device which generates video information including aplurality of video units, wherein the frequency of the audio unit issubstantially equal to an integer multiple of a frequency of the videounit.
 20. The information recording apparatus according to claim 19,wherein there are a plurality of different kinds of frequencies as thefrequency of the video unit, and the frequency of the audio unit issubstantially equal to an integer multiple of a least common multiple ofthe different kinds of frequencies.
 21. An information reproducingapparatus for reproducing information recorded on an informationrecording medium comprising: audio information which comprises aplurality of audio units, sampled by a predetermined sampling frequencyand quantized by a predetermined quantization bit; and time managementinformation indicating a presentation time, by a predeterminedspecification frequency, at which the audio information is to bereproduced, wherein a frequency of the audio unit is 1/n (n: naturalnumber) of the sampling frequency and 1/n (in: natural number) of thespecification frequency; the apparatus comprising: a reading devicewhich reads information recorded on the information recording medium; ademodulating device which demodulates the information read by thereading device, thereby obtaining a demodulation signal; an extractingdevice which extracts the audio information from the demodulationsignal; and an audio decoder which decodes the audio information. 22.The information reproducing apparatus according to claim 21, wherein thesampling frequency is selected from a plurality of sampling frequencies,and the quantization bit is selected from a plurality of quantizationbits.
 23. The information reproducing apparatus according to claim 21,wherein the audio information has a predetermined number of audiochannels.
 24. The information reproducing apparatus according to claim21, wherein the sampling frequency is selected from a plurality ofsampling frequencies, and the quantization bit is selected from aplurality of quantization bits, wherein the audio information has apredetermined number of audio channels, and wherein a plurality ofcombination of the sampling frequency, the quantization bit and thenumber of audio channels are defined in order for a data rate of theaudio information to be less than a predetermined value.
 25. Theinformation reproducing apparatus according to claim 21, wherein theaudio information is divided into a plurality audio packets, eachincluding the time management information.
 26. The informationreproducing apparatus according to claim 25, wherein the time managementinformation indicates the presentation time at which the audioinformation in the corresponding audio packet is to be reproduced,wherein the audio decoder decodes the audio information in accordancewith the time management information.
 27. The information reproducingapparatus according to claim 25, wherein each of the audio packetscomprises a header portion which includes the time managementinformation.
 28. The information reproducing apparatus according toclaim 27, wherein the time management information indicates thepresentation time at which a first audio unit having a head portion inthe corresponding audio packet is to be reproduced.
 29. The informationreproducing apparatus according to claim 21, wherein the informationrecording medium further comprises video information including aplurality of video units, wherein the frequency of the audio unit issubstantially equal to an integer multiple of a frequency of the videounit, and wherein the apparatus further comprises a video decoder whichdecodes the video information.
 30. The information reproducing apparatusaccording to claim 29, wherein there are a plurality of different kindsof frequencies as the frequency of the video unit, and the frequency ofthe audio unit is substantially equal to an integer multiple of a leastcommon multiple of the different kinds of frequencies.
 31. A method forrecording information, comprising the steps of: generating audioinformation which comprises a plurality of audio units, sampled by apredetermined sampling frequency and quantized by a predeterminedquantization bit; generating time management information indicating apresentation time, by a predetermined specification frequency, at whichthe audio information is to be reproduced; and recording the audioinformation and the time management information on a recording medium,wherein a frequency of the audio unit is 1/n (n: natural number) of thesampling frequency and 1/n (in: natural number) of the specificationfrequency.
 32. The method according to claim 31, wherein the samplingfrequency is selected from a plurality of sampling frequencies, and thequantization bit is selected from a plurality of quantization bits. 33.The method according to claim 31, wherein the audio information has apredetermined number of audio channels.
 34. The method according toclaim 31, wherein the sampling frequency is selected from a plurality ofsampling frequencies, and the quantization bit is selected from aplurality of quantization bits, wherein the audio information has apredetermined number of audio channels, and wherein a plurality ofcombination of the sampling frequency, the quantization bit and thenumber of audio channels are defined in order for a data rate of theaudio information to be less than a predetermined value.
 35. The methodaccording to claim 31, wherein the audio information is divided into aplurality of audio packets, each including the time managementinformation.
 36. The method according to claim 35, wherein the timemanagement information indicates the time at which the audio informationin the corresponding audio packet is to be reproduced.
 37. The methodaccording to claim 35, wherein each of the audio packets comprises aheader portion which includes the time management information.
 38. Themethod according to claim 37, wherein the time management informationindicates the time at which a first audio unit having a head portion inthe corresponding audio packet is to be reproduced.
 39. The methodaccording to claim 31, further comprising a step of generating videoinformation including a plurality of video units, wherein the frequencyof the audio unit is substantially equal to an integer multiple of afrequency of the video unit.
 40. The method according to claim 39,wherein there are a plurality of different kinds of frequencies as thefrequency of the video unit, and the frequency of the audio unit issubstantially equal to an integer multiple of a least common multiple ofthe different kinds of frequencies.
 41. A method for reproducinginformation recorded on an information recording medium comprising:audio information which comprises a plurality of audio units, sampled bya predetermined sampling frequency and quantized by a predeterminedquantization bit; and time management information indicating apresentation time, by a predetermined specification frequency, at whichthe audio information is to be reproduced, wherein a frequency of theaudio unit is 1/n (n: natural number) of the sampling frequency and 1/n(in: natural number) of the specification frequency, the methodcomprising the steps of: reading information recorded on the informationrecording medium; demodulating the information read by the readingdevice, thereby obtaining a demodulation signal; extracting the audioinformation from the demodulation signal; and decoding the audioinformation.
 42. The method according to claim 41, wherein the samplingfrequency is selected from a plurality of sampling frequencies, and thequantization bit is selected from a plurality of quantization bits. 43.The method according to claim 41, wherein the audio information has apredetermined number of audio channels.
 44. The method according toclaim 41, wherein the sampling frequency is selected from a plurality ofsampling frequencies, and the quantization bit is selected from aplurality of quantization bits, wherein the audio information has apredetermined number of audio channels, and wherein a plurality ofcombination of the sampling frequency, the quantization bit and thenumber of audio channels are defined in order for a data rate of theaudio information to be less than a predetermined value.
 45. The methodaccording to claim 41, wherein the audio information is divided into aplurality of audio packets, each including the time managementinformation.
 46. The method according to claim 45, wherein the timemanagement information indicates the time at which the audio informationin the corresponding audio packet is to be reproduced, in the decodingstep the audio information is decoded in accordance with the timemanagement information.
 47. The method according to claim 45, whereineach of the audio packets comprises a header portion which includes thetime management information.
 48. The method according to claim 47,wherein the time management information indicates the time at which afirst audio unit having a head portion in the corresponding audio packetis to be reproduced.
 49. The method according to claim 41, wherein theinformation recording medium further comprises video informationincluding a plurality of video units, wherein the frequency of the audiounit is substantially equal to an integer multiple of a frequency of thevideo unit, and wherein the method further comprises a step of decodingthe video information.
 50. The method according to claim 49, whereinthere are a plurality of different kinds of frequencies as the frequencyof the video unit, and the frequency of the audio unit is substantiallyequal to an integer multiple of a least common multiple of the differentkinds of frequencies.